Slide-valve for steam-engines



(ModeL) .0. MILLER.

Slide Valve for Steam "Engines. "No. 237,302. Patented Feb. 1,1881.

Z CI/7 UNiTED STATES PATENT QFFICLEQ CHARLES MILLER, OF BOONVILIlE,MISSOURI.

SLIDE-VALVE FOR STEAM-ENGINES.

SPECIFICATION formingpart of Letters Patent No. 237,302, dated February1, 1881.

Application filed October 15, 1880. (Model) To all whom it may concern:

Be it known that I, CHARLES MILLER, of Boonville, in the county ofCooper and State of Missouri, have invented a new and ImprovedSlideValve for Steam-Engines; and I do hereby declare that the followingis a full and exact description of the said invention.

My invention relates to an improvement in slide-valves forsteam-engines, the object being to provide a valve of such constructionas to dispense with the ordinary steam-chest, to reduce the friction ofthe valve on its seat, so that the valve may be operated by a minimumexpenditure of power, and to simplify the construction and cheapen thecost of this type of valves.

With these ends in view my invention consists in a slide valve embodyingcertain features of construction and combinations of parts, as willhereinafter be explained, and pointed out in the claims.

In the accompanying drawings, Figure 1 shows a plan and transversesection of the valve-seat. Fig. 2 shows a plan View of the under side ofthe valve and a transverse section of the same; and Fig. 3 is a view, inperspective, of the valve located in its seat.

As illustrated in Fig. 1, the valve-seat is cast solid upon thecylinder, or made separate therefrom and secured to the cylinder in anydesired manner. The valve-seat is furnished with side flanges or ledges,between which the valve-seat reciprocates, and is thereby retainedagainst displacement. The valve-seat may be constructed on the middle ofthe cylinder of a single-valve engine, or at both ends of a double-valveengine. The valve-seat is furnished with the elongated supply-port a a,which communicates with the passage through which steam is received fromthe steam-boiler.

Ports 1) I), located on opposite sides of the exhaust-port c, conveysteam to the cylinderports.

The slide-valve, as shown in Fig. 2, is furnished with a centralexhaust-arch, on opposite ends of which are located the ports d d, whichcommunicate with each other by a channel on one side of the valve, andwith an elongated port, 6 e, on the opposite side of the valve. Asteam-passage, f, leads from the port 6 e upwardly and over the centerof the exhaust-arch, and then upwardly, and opens in the center of thebottom of the cylinder h. Within the cylinder h is located a smallpiston, i, having afriction-roller journaled in its upper end.

g represents a spring-arm, secured at its lower end to the valve-seat,and its upper and free end resting upon the friction-roller.

K represents the valve-stem.

As steam enters the induction-passage to the valve-seat it flowsupwardly through the port a a in the valve-seat and through port 06 toeither one of the ports d cl, according to the position of the valve.The pressure of the steam on the under face of the valve tends tolift itfrom its seat, and to counteract such upward pressure a portion of thesteam is allowed to flow upwardly through the steampassage f and againstthe bottom of piston i, the reaction of the steam on the lower face ofthe piston 71 serving to counterbalance the upward pressure on thevalve, as the area of the lower end of the piston is equal to that ofthe three supply-ports.

The piston is retained in place by the arm g,

and but slight friction is created on the piston by reason of thefriction-roller i being interposed between the parts.

Having fully described my invention, what I claim as new, and desire tosecure by Letters Patent, isi 1. The combination, with'a valve-seathaving supply and exhaust ports, substantially as shown, of the valveprovided with the three supply-ports, central exhaust-arch, and channelsconnecting the supply-ports, substantially as set forth.

2. The combination, with a valve-seat having supply and exhaust ports,substantially as shown, of the valve provided withthe threesupply-ports, central exhaust-arch, connecting-channels, andsteampassage f, leading from one of the supply-ports to the lower end ofv a steam-cylinder located over the center of the valve, substantiallyas set forth.

3. The combination, with the valve provided With supply-ports andc0nnecting-channels, substantially as shown, of cylinder h, piston 11,and steam-passage f, substantially as 5 setforth.

4. The combination, with the valve having the supply-ports andconnecting-channels, sub,-

st-antially as shown, of the cylinder h, piston i, friction-roller, armg, and steam-passage f, substantially as set forth.

CHARLES MILLER.

W'itnesses:

NIGHQLAUS WALZ, G. L. BRENNEISEN.

